package com.tcm.training.admin.system.service;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.tcm.training.admin.common.PageResponse;
import com.tcm.training.admin.system.dto.CommonQuestionSaveRequest;
import com.tcm.training.admin.system.entity.CommonQuestion;
import com.tcm.training.admin.system.mapper.CommonQuestionMapper;
import com.tcm.training.admin.system.vo.CommonQuestionDetailVO;
import com.tcm.training.admin.system.vo.CommonQuestionListItemVO;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.ArrayList;
import java.util.List;

@Service
public class CommonQuestionAppService {

    private final CommonQuestionMapper commonQuestionMapper;

    public CommonQuestionAppService(CommonQuestionMapper commonQuestionMapper) {
        this.commonQuestionMapper = commonQuestionMapper;
    }

    public PageResponse<CommonQuestionListItemVO> page(int page, int pageSize, String title) {
        LambdaQueryWrapper<CommonQuestion> queryWrapper = new LambdaQueryWrapper<CommonQuestion>()
                .eq(CommonQuestion::getDeleted, 0)
                .like(title != null && !title.trim().isEmpty(), CommonQuestion::getTitle, title == null ? null : title.trim())
                .orderByDesc(CommonQuestion::getCreatedAt)
                .orderByDesc(CommonQuestion::getId);
        IPage<CommonQuestion> result = commonQuestionMapper.selectPage(new Page<CommonQuestion>(page, pageSize), queryWrapper);
        List<CommonQuestionListItemVO> list = new ArrayList<CommonQuestionListItemVO>();
        for (CommonQuestion item : result.getRecords()) {
            list.add(toListItem(item));
        }
        return PageResponse.of(list, result.getTotal(), result.getCurrent(), result.getSize());
    }

    public CommonQuestionDetailVO detail(Long id) {
        return toDetailVO(requireItem(id));
    }

    @Transactional
    public CommonQuestionDetailVO create(CommonQuestionSaveRequest request) {
        CommonQuestion item = new CommonQuestion();
        fillEntity(item, request);
        item.setDeleted(0);
        commonQuestionMapper.insert(item);
        return detail(item.getId());
    }

    @Transactional
    public CommonQuestionDetailVO update(Long id, CommonQuestionSaveRequest request) {
        CommonQuestion item = requireItem(id);
        fillEntity(item, request);
        commonQuestionMapper.updateById(item);
        return detail(id);
    }

    @Transactional
    public void delete(Long id) {
        requireItem(id);
        commonQuestionMapper.deleteById(id);
    }

    private void fillEntity(CommonQuestion item, CommonQuestionSaveRequest request) {
        item.setTitle(normalizeTitle(request.getTitle()));
        item.setContentHtml(normalizeContent(request.getContentHtml()));
    }

    private CommonQuestion requireItem(Long id) {
        CommonQuestion item = commonQuestionMapper.selectOne(new LambdaQueryWrapper<CommonQuestion>()
                .eq(CommonQuestion::getId, id)
                .eq(CommonQuestion::getDeleted, 0)
                .last("limit 1"));
        if (item == null) {
            throw new IllegalArgumentException("常见问题不存在");
        }
        return item;
    }

    private CommonQuestionListItemVO toListItem(CommonQuestion item) {
        CommonQuestionListItemVO vo = new CommonQuestionListItemVO();
        vo.setId(item.getId());
        vo.setTitle(item.getTitle());
        vo.setCreatedAt(item.getCreatedAt());
        return vo;
    }

    private CommonQuestionDetailVO toDetailVO(CommonQuestion item) {
        CommonQuestionDetailVO vo = new CommonQuestionDetailVO();
        vo.setId(item.getId());
        vo.setTitle(item.getTitle());
        vo.setContentHtml(item.getContentHtml());
        vo.setCreatedAt(item.getCreatedAt());
        vo.setUpdatedAt(item.getUpdatedAt());
        return vo;
    }

    private String normalizeTitle(String title) {
        String trimmed = trimToNull(title);
        if (trimmed == null) {
            throw new IllegalArgumentException("请输入问题");
        }
        if (trimmed.length() > 15) {
            throw new IllegalArgumentException("请输入15个字以内");
        }
        return trimmed;
    }

    private String normalizeContent(String contentHtml) {
        String trimmed = trimToNull(contentHtml);
        if (trimmed == null || isBlankRichText(trimmed)) {
            throw new IllegalArgumentException("请输入内容");
        }
        return trimmed;
    }

    private boolean isBlankRichText(String html) {
        String normalized = html
                .replaceAll("(?i)<br\\s*/?>", "")
                .replaceAll("(?i)</p>", "")
                .replace("&nbsp;", "")
                .replace("&#160;", "")
                .replaceAll("<[^>]+>", "")
                .trim();
        if (!normalized.isEmpty()) {
            return false;
        }
        String lowerCaseHtml = html.toLowerCase();
        return !lowerCaseHtml.contains("<img")
                && !lowerCaseHtml.contains("<video")
                && !lowerCaseHtml.contains("<audio")
                && !lowerCaseHtml.contains("<iframe");
    }

    private String trimToNull(String value) {
        if (value == null) {
            return null;
        }
        String trimmed = value.trim();
        return trimmed.isEmpty() ? null : trimmed;
    }
}